Both Samsung SL820 and Samsung EX2F have 12.0 MP resolution sensors but Samsung SL820's sensor is 1/2.3-inch (6.08 x 4.56 mm ) and Samsung EX2F's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Samsung EX2F's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Samsung SL820.
Below you can see the SL820 and EX2F sensor size comparison.
Sensor Size and Resolution Comparison image of Samsung SL820 and Samsung EX2F Cameras
As seen above, Samsung EX2F has a 1.5x Larger sensor area than Samsung SL820. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Samsung SL820
or the
Samsung EX2F ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus 1/1.7-inch),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.